Re: [PATCH] cpuidle: riscv-sbi: Fix CPU_PM_CPU_IDLE_ENTER_xyz() macro usage

From: Palmer Dabbelt
Date: Fri Sep 23 2022 - 06:57:00 EST


On Thu, 22 Sep 2022 10:07:46 PDT (-0700), Palmer Dabbelt wrote:
> On Sun, 28 Aug 2022 19:59:45 PDT (-0700), anup@xxxxxxxxxxxxxx wrote:
>> Hi Palmer,
>>
>> On Mon, Jul 18, 2022 at 2:16 PM Anup Patel <apatel@xxxxxxxxxxxxxxxx> wrote:
>>>
>>> Currently, we are using CPU_PM_CPU_IDLE_ENTER_PARAM() for all SBI HSM
>>> suspend types so retentive suspend types are also treated non-retentive
>>> and kernel will do redundant additional work for these states.
>>>
>>> The BIT[31] of SBI HSM suspend types allows us to differentiate between
>>> retentive and non-retentive suspend types so we should use this BIT
>>> to call appropriate CPU_PM_CPU_IDLE_ENTER_xyz() macro.
>>>
>>> Fixes: 6abf32f1d9c5 ("cpuidle: Add RISC-V SBI CPU idle driver")
>>> Signed-off-by: Anup Patel <apatel@xxxxxxxxxxxxxxxx>
>>
>> Can you please take this patch through the RISC-V tree ?
>
> Sorry I missed this, I didn't realize you wanted me to merge it. It's
> on fixes.

Actually from reading this again, it's not really a fix: the kernel is
correct without this change, it's just going to save/restore when it
doesn't need to. So I'm queuing this into for-next instead.

>
>>
>> Regards,
>> Anup
>>
>>> ---
>>> drivers/cpuidle/cpuidle-riscv-sbi.c | 7 ++++++-
>>> 1 file changed, 6 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/cpuidle/cpuidle-riscv-sbi.c b/drivers/cpuidle/cpuidle-riscv-sbi.c
>>> index 1151e5e2ba82..33c92fec4365 100644
>>> --- a/drivers/cpuidle/cpuidle-riscv-sbi.c
>>> +++ b/drivers/cpuidle/cpuidle-riscv-sbi.c
>>> @@ -97,8 +97,13 @@ static int sbi_cpuidle_enter_state(struct cpuidle_device *dev,
>>> struct cpuidle_driver *drv, int idx)
>>> {
>>> u32 *states = __this_cpu_read(sbi_cpuidle_data.states);
>>> + u32 state = states[idx];
>>>
>>> - return CPU_PM_CPU_IDLE_ENTER_PARAM(sbi_suspend, idx, states[idx]);
>>> + if (state & SBI_HSM_SUSP_NON_RET_BIT)
>>> + return CPU_PM_CPU_IDLE_ENTER_PARAM(sbi_suspend, idx, state);
>>> + else
>>> + return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(sbi_suspend,
>>> + idx, state);
>>> }
>>>
>>> static int __sbi_enter_domain_idle_state(struct cpuidle_device *dev,
>>> --
>>> 2.34.1
>>>